Liquid crystal display having improved color display

ABSTRACT

A liquid crystal display includes: a first pixel and a second pixel for displaying different colors, the first pixel and the second pixel each including a first sub-pixel electrode receiving a first voltage; a second sub-pixel electrode receiving a second voltage; an insulating layer disposed between the first sub-pixel electrode and the second sub-pixel electrode; and a common electrode receiving a common voltage. A first portion of the first sub-pixel electrode and a second portion of the second sub-pixel electrode overlap each other, a difference between the first voltage and the common voltage is larger than a difference between the second voltage and the common voltage, and a ratio of the second voltage to the first voltage for the first pixel is different from a ratio of the second voltage to the first voltage for the second pixel.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to, and the benefit of, Korean PatentApplication No. 10-2015-0024467 filed in the Korean IntellectualProperty Office on Feb. 17, 2015, the entire contents of which areincorporated herein by reference.

BACKGROUND

(a) Technical Field

Embodiments of the present invention relate generally to flat paneldisplays. More specifically, embodiments of the present invention relateto liquid crystal displays having improved color display.

(b) Description of the Related Art

A liquid crystal display is a common form of flat panel display thattypically includes two display panels where field generating electrodessuch as a pixel electrode and a common electrode are formed, with aliquid crystal layer interposed therebetween.

The liquid crystal display generates an electric field in a liquidcrystal layer by applying voltages to the field generating electrodes,to determine orientations of liquid crystal molecules of the liquidcrystal layer and to thereby control polarization of incident light,thus displaying an image.

The liquid crystal display includes switching elements each connected topixel electrodes, and a plurality of signal lines such as data lines andgate lines for applying voltages to the pixel electrodes by controllingthe switching elements.

A vertical alignment (VA) mode liquid crystal display is one in whichthe longitudinal axes of the liquid crystal molecules are arranged to beperpendicular to the upper and lower display panels when no electricfield is applied. VA mode liquid crystal displays are characterized byrelatively large contrast ratio and large reference viewing angle.

In order to create a side visibility that is approximately equal tofront visibility in the vertical alignment mode LCD, a method of causinga difference in transmittance by dividing one pixel into two subpixelsand applying different voltages to the two subpixels has been suggested.However, when dividing one pixel into two subpixels and differentiatingtransmittance, the luminance is increased at a low gray or high graysuch that gray expression is difficult at the side, therebydeteriorating display quality. Also, when the grays of the plurality ofpixels displaying different colors are equal to each other, due to thecolor display deviation, a color tone is changed.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY

Embodiments of the present invention provide a liquid crystal displayhaving the advantages of eliminating a color tone change by preventingcolor display deviation, expressing an accurate gray in a low grayregion, and preventing transmittance deterioration while side visibilityis close to front visibility.

A liquid crystal display according to an exemplary embodiment of thepresent invention includes: a first pixel and a second pixel displayingdifferent colors, the first pixel and the second pixel each including afirst substrate; a first sub-pixel electrode disposed on the firstsubstrate and receiving a first voltage; a second sub-pixel electrodedisposed on the first substrate and receiving a second voltage; aninsulating layer disposed between the first sub-pixel electrode and thesecond sub-pixel electrode; a second substrate facing the firstsubstrate; and a common electrode disposed on the second substrate andreceiving a common voltage. A first portion of the first sub-pixelelectrode and a second portion of the second sub-pixel electrode overlapeach other, a difference between the first voltage and the commonvoltage is larger than a difference between the second voltage and thecommon voltage, and a ratio of the second voltage to the first voltagefor the first pixel is different from a ratio of the second voltage tothe first voltage for the second pixel.

Each of the first and second pixels may further include: a firstswitching element connected to the first sub-pixel electrode; and asecond switching element and a third switching element connected to thesecond sub-pixel electrode, wherein a ratio of a channel length to achannel width of one of the second switching element and the thirdswitching element of the first pixel may be different from a ratio ofthe channel length to the channel width of one of the second switchingelement and the third switching element of the second pixel.

For each of the first and second pixels, the first portion of the firstsub-pixel electrode may include a first subregion disposed under theinsulating layer and a second subregion disposed on the insulatinglayer, and the first subregion and the second subregion may be connectedto each other through a contact hole formed in the insulating layer.

Each of the first and second pixels may further include a gate lineformed on the first substrate. For each of the first and second pixels,the second subregion of the first sub-pixel electrode may include aplurality of first branch electrodes, the second sub-pixel electrode mayinclude a plurality of second branch electrodes, and a first anglebetween the first branch electrodes of the second subregion of the firstpixel and the gate line may be different from a second angle between thefirst branch electrodes of the second subregion of the second pixel andthe gate line.

For each of the first and second pixels, a size of an area of the secondsubregion of the first pixel may be different from a size of an area ofthe second subregion of the second pixel.

For each of the first and second pixels, the first portion of the firstsub-pixel electrode may be substantially planar, and the second branchelectrodes may collectively extend along a plurality of differentdirections.

A liquid crystal display according to another exemplary embodiment ofthe present invention may include: a first pixel and a second pixeldisplaying different colors, the first pixel and the second pixel eachinclude a first substrate; a first sub-pixel electrode disposed on thefirst substrate and receiving a first voltage; a second sub-pixelelectrode disposed on the first substrate and receiving a secondvoltage; and an insulating layer disposed between the first sub-pixelelectrode and the second sub-pixel electrode. One pixel area includes afirst region where a first portion of the first sub-pixel electrode isdisposed, a second region where the second portion of the firstsub-pixel electrode and a third portion of the second sub-pixelelectrode overlap each other, and a third region where a fourth portionof the second sub-pixel electrode is disposed, and a ratio of the secondvoltage to the first voltage of the first pixel is different from aratio of the second voltage to the first voltage of the second pixel.

According to exemplary embodiments of the present invention, an accurategray in a low gray region may be expressed, and the transmittancedeterioration may be prevented while side visibility may be maintainedclose to front visibility. Also, by preventing color display deviation,color tone change may be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a layout view of a liquid crystal display according to anexemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of the liquid crystal display of FIG. 1taken along a line II-II.

FIG. 3 is a layout view of a first sub-pixel electrode of the liquidcrystal display of FIG. 1.

FIG. 4 is a layout view of a portion of a first sub-pixel electrode anda second sub-pixel electrode of the liquid crystal display of FIG. 1.

FIG. 5 is a cross-sectional view of the liquid crystal display of FIG. 1taken along a line V-V.

FIG. 6 is a cross-sectional view of the liquid crystal display of FIG. 1taken along a line VI-VI.

FIG. 7 is a cross-sectional view of the liquid crystal display of FIG. 1taken along a line VII-VII.

FIG. 8 is a layout view of a second pixel of a liquid crystal displayaccording to another exemplary embodiment of the present invention.

FIG. 9 is a layout view of a first sub-pixel electrode of a second pixelof the liquid crystal display of FIG. 8.

FIG. 10 is a layout view of a portion of a first sub-pixel electrode anda second sub-pixel electrode of a second pixel of the liquid crystaldisplay of FIG. 8.

FIG. 11 is a layout view of a second pixel of a liquid crystal displayaccording to another exemplary embodiment of the present invention.

FIG. 12 is a layout view of a first sub-pixel electrode of a secondpixel of the liquid crystal display of FIG. 11.

FIG. 13 is a layout view of a portion of a first sub-pixel electrode anda second sub-pixel electrode of a second pixel of the liquid crystaldisplay of FIG. 11.

FIG. 14 and FIG. 15 are graphs showing the results of an experimentalimplementation of the present invention.

FIG. 16 and FIG. 17 are graphs showing further results of anexperimental implementation of the present invention.

FIG. 18 is a graph showing a result of another experimentalimplementation of the present invention.

FIG. 19 illustrates an equivalent circuit of a pixel of embodiments ofthe present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the present invention will be described indetail with reference to the attached drawings. The present inventionmay be modified in many different forms and should not be construed asbeing limited to the exemplary embodiments set forth herein. Rather, theexemplary embodiments of the present invention are provided so that thisdisclosure will be thorough and complete, and will fully convey theconcept of the present invention to those skilled in the art.

In the drawings, the thickness of layers and regions may be exaggeratedfor clarity. The various Figures thus may not be to scale. In addition,when a layer is described to be formed on another layer or on asubstrate, this means that the layer may be formed on the other layer oron the substrate, or a third layer may be interposed between the layerand the other layer or the substrate. Like numbers refer to likeelements throughout the specification. All numerical values areapproximate, and may vary. All examples of specific materials andcompositions are to be taken as nonlimiting and exemplary only. Othersuitable materials and compositions may be used instead.

Now, a liquid crystal display according to an exemplary embodiment ofthe present invention will be described with reference to FIG. 1 to FIG.7. FIG. 1 is a layout view of a liquid crystal display according to anexemplary embodiment of the present invention. FIG. 2 is across-sectional view of the liquid crystal display of FIG. 1 taken alonga line II-II. FIG. 3 is a layout view of a first sub-pixel electrode ofthe liquid crystal display of FIG. 1. FIG. 4 is a layout view of aportion of a first sub-pixel electrode and a second sub-pixel electrodeof the liquid crystal display of FIG. 1. FIG. 5 is a cross-sectionalview of the liquid crystal display of FIG. 1 taken along a line V-V.FIG. 6 is a cross-sectional view of the liquid crystal display of FIG. 1taken along a line VI-VI. FIG. 7 is a cross-sectional view of the liquidcrystal display of FIG. 1 taken along a line VII-VII.

First, referring to FIG. 1 and FIG. 2, a liquid crystal displayaccording to the present exemplary embodiment includes a lower panel 100and an upper panel 200 facing each other, and a liquid crystal layer 3interposed between the two display panels 100 and 200.

Firstly, the lower panel 100 will be described.

A gate line 121, a reference voltage line 131, and a storage electrode135 are formed on a first substrate 110 made of transparent glass orplastic. The gate line 121 transfers a gate signal and mainly extends ina transverse direction. The gate line 121 includes a first gateelectrode 124 a, a second gate electrode 124 b, a third gate electrode124 c, and a wide end (not shown) for connection to other layers or toan external driving circuit.

The reference voltage line 131 may extend substantially parallel to thegate line 121 and have an expansion 136, and the expansion 136 isconnected to a third drain electrode 175 c that will be described later.The reference voltage line 131 includes the storage electrode 135enclosing a pixel area.

A gate insulating layer 140 is formed on the gate line 121, thereference voltage line 131, and the storage electrode 135.

A first semiconductor 154 a, a second semiconductor 154 b, and a thirdsemiconductor 154 c that may be made of amorphous silicon or crystallinesilicon are formed on the gate insulating layer 140.

A plurality of ohmic contacts 163 a, 163 b, 163 c, 165 a, and 165 b areformed on the first semiconductor 154 a, the second semiconductor 154 b,and the third semiconductor 154 c. When the semiconductors 154 a, 154 b,and 154 c are formed with an oxide semiconductor, the ohmic contacts maybe omitted.

Data conductors including a data line 171, a first source electrode 173a and a second source electrode 173 b, a first drain electrode 175 a, asecond drain electrode 175 b, a third source electrode 173 c, and thethird drain electrode 175 c are formed on the ohmic contacts 163 a, 163b, 163 c, 165 a, and 165 b and the gate insulating layer 140.

The second drain electrode 175 b is connected to the third sourceelectrode 173 c.

The first gate electrode 124 a, the first source electrode 173 a, andthe first drain electrode 175 a collectively form a first thin filmtransistor Qa along with the first semiconductor 154 a, and a channel ofthe thin film transistor is formed in the semiconductor 154 a betweenthe first source electrode 173 a and the first drain electrode 175 a.Similarly, the second gate electrode 124 b, the second source electrode173 b, and the second drain electrode 175 b collectively form a secondthin film transistor Qb along with the second semiconductor 154 b, and achannel of the thin film transistor is formed in the semiconductor 154 bbetween the second source electrode 173 b and the second drain electrode175 b. Likewise, the third gate electrode 124 c, the third sourceelectrode 173 c, and the third drain electrode 175 c collectively form athird thin film transistor Qc along with the third semiconductor 154 c,and a channel of the thin film transistor is formed in the semiconductor154 c between the third source electrode 173 c and the third drainelectrode 175 c.

A first passivation layer 180 a that may be made of an inorganicinsulator such as a silicon nitride or a silicon oxide is formed on thedata conductors 171, 173 a, 173 b, 173 c, 175 a, 175 b, and 175 c andexposed portions of the semiconductors 154 a, 154 b, and 154 c.

A color filter 230 is disposed on the first passivation layer 180 a.

A light blocking member (not shown) may be disposed on a region wherethe color filter 230 is not disposed and on a portion of the colorfilter 230. The light blocking member can be referred to as a blackmatrix and prevents light leakage.

An overcoat (capping layer) 80 is disposed on the color filter 230. Theovercoat 80 prevents peeling of the color filter 230 and the lightblocking member, and suppresses contamination of the liquid crystallayer 3 by an organic material of the solvent that flows from the colorfilter 230, so that it prevents defects such as afterimages that mayoccur when an image is driven.

Also, at least one of the color filter 230 and the light blocking membermay be formed on the second display panel 200 rather than the firstdisplay panel 100.

A pixel electrode 191 is formed to include a first subpixel electrode191 a and a second subpixel electrode 191 b. The first subpixelelectrode 191 a includes a first subregion 191 a 1 and a secondsubregion 191 a 2. The first subregion 191 a 1 of the first subpixelelectrode 191 a is disposed on the capping layer 80.

Referring to FIG. 3, the first subregion 191 a 1 of the first subpixelelectrode 191 a has a shape in plan view that includes a cross-shapedconnection portion disposed at the center of the pixel area, and fourparallelograms which are disposed around the cross-shaped connectionportion to surround the cross-shaped connection portion. A firstextension portion 193 is disposed at the center of the cross-shapedconnection portion. Further, a protrusion extending upward and downwardfrom a horizontal center of the pixel area is formed. As such, the firstsubregion 191 a 1 of the first subpixel electrode 191 a is disposedwithin the pixel area.

The second passivation layer 180 b is disposed on the capping layer 80and the first subregion 191 a 1 of the first subpixel electrode 191 a.

The second subregion 191 a 2 of the first subpixel electrode 191 a, andthe second subpixel electrode 191 b, are disposed on the secondpassivation layer 180 b.

Referring to FIG. 4, the second subregion 191 a 2 of the first subpixelelectrode 191 a is disposed at the central portion of its pixel, and theoverall shape thereof is rhomboidal. The second subregion 191 a 2 of thefirst subpixel electrode 191 a includes a cross stem including atransverse part and a longitudinal part, and a plurality of first branchelectrodes 194 extending from the cross stem. The first branchelectrodes 194 extend in four different directions.

The second sub-pixel electrode 191 b is formed to enclose the secondsubregion 191 a 2 of the first sub-pixel electrode 191 a. The secondsub-pixel electrode 191 b includes an outer stem 192 a formed to enclosethe second subregion 191 a 2 of the first sub-pixel electrode 191 a, anda plurality of second branch electrodes 195 extend from the outer stem192 a.

Some of the second branch electrodes 195 of the second sub-pixelelectrode 191 b overlap the first subregion 191 a 1 of the firstsub-pixel electrode 191 a.

The first passivation layer 180 a and the overcoat 80 have a firstcontact hole 185 a formed therein and exposing a portion of the firstdrain electrode 175 a; and the first passivation layer 180 a, theovercoat 80, and the second passivation layer 180 b have a secondcontact hole 185 b exposing a portion of the second drain electrode 175b. The gate insulating layer 140, first passivation layer 180 a, and theovercoat 80 have a third contact hole 185 c exposing a portion of theexpansion 136 of the third drain electrode 175 c. Also, the secondpassivation layer 180 b has a fourth contact hole 186 exposing thecenter portion of the first subregion 191 a 1 of the first sub-pixelelectrode 191 a.

The first subregion 191 a 1 of the first sub-pixel electrode 191 a isphysically and electrically connected to the first drain electrode 175 athrough the first contact hole 185 a, and the second sub-pixel electrode191 b is physically and electrically connected to the second drainelectrode 175 b through the second contact hole 185 b. Also, the secondsubregion 191 a 2 of the first sub-pixel electrode 191 a is connected tothe first extension portion 193 of the first sub-pixel electrode 191 athrough the fourth contact hole 186 formed in the second passivationlayer 180 b.

The first sub-pixel electrode 191 a and the second sub-pixel electrode191 b receive the data voltage from the first drain electrode 175 a andthe second drain electrode 175 b via the first contact hole 185 a andthe second contact hole 185 b.

Next, the second display panel 200 will be described.

A light blocking member 220 and a common electrode 270 are formed on asecond substrate 210 made of transparent glass or plastic.

However, in a case of a liquid crystal display according to anotherexemplary embodiment of the present invention, the light blocking member220 may alternatively be disposed on the first display panel 100, and ina case of a liquid crystal display according to a further exemplaryembodiment, the color filter disposed may alternatively be disposed inthe second display panel 200.

Alignment layers (not shown) may be formed on inner surfaces of thedisplay panels 100 and 200, and they may be vertical alignment layers.

A polarizer (not shown) may be provided on the outer surface of each ofthe two display panels 100 and 200. It is preferable that transmissiveaxes of the two polarizers be orthogonal to each other and that eithertransmissive axis is parallel to the gate line 121. However, thepolarizer may only be disposed at one outer surface of the two displaypanels 100 and 200.

The liquid crystal layer 3 has negative dielectric anisotropy, and theliquid crystal molecules of the liquid crystal layer 3 may be aligned sothat long axes thereof are perpendicular to the surface of the twodisplay panels 100 and 200 in a state in which there is no electricfield applied. Therefore, the incident light does not pass through thecrossed polarizers but is blocked in a state in which there is noelectric field.

At least one of the liquid crystal layer 3 and the alignment layer mayinclude a photo-reactive material, more specifically, a reactivemesogen.

Next, a driving method for a liquid crystal display according to theexemplary embodiment of the present invention will be briefly described.

If a gate-on signal is applied to the gate line 121, the first gateelectrode 124 a, the second gate electrode 124 b, and the third gateelectrode 124 c receive the gate-on signal such that the first switchingelement Qa, the second switching element Qb, and the third switchingelement Qc are turned on. Accordingly, the data voltage applied to thedata line 171 is applied to the first subpixel electrode 191 a and thesecond subpixel electrode 191 b through the turned-on first switchingelement Qa and second switching element Qb. The voltage applied to thesecond subpixel electrode 191 b is divided through the third switchingelement Qc connected in parallel to the second switching element Qb.Accordingly, the voltage applied to the second subpixel electrode 191 bis lower than the voltage applied to the first subpixel electrode 191 a.

In this case, an equivalent circuit diagram between the data linetransmitting the data voltage and the reference voltage linetransmitting the voltage division reference voltage will be described.FIG. 19 illustrates this equivalent circuit diagram.

In FIG. 19, Vp is a second pixel voltage applied to the second sub-pixelelectrode 191 b, Vd is a data voltage applied to the data line 171, Vcstis a voltage division reference voltage, Rp is a first resistance valueof a second switching element Qb connected between the data line and thesecond sub-pixel electrode 191 b, and Rrd is a second resistance valueof a third switching element Qc connected between the second sub-pixelelectrode 191 b and the voltage division reference voltage line 131.

The second pixel voltage Vp applied to the second sub-pixel electrode191 b is determined by the first resistance value Rp of the secondswitching element Qb, and the second resistance value Rrd of the thirdswitching element Qc.

A current value flowing to the second sub-pixel electrode 191 b isdetermined by a difference between the data voltage Vd and the secondpixel voltage Vp divided by the first resistance value Rp, and is alsothe same as the difference between the second pixel voltage Vp and thevoltage division reference voltage Vcst divided by the second resistancevalue Rrd.

Accordingly, the following equation is satisfied.

$\frac{\left( {{Vd} - {Vp}} \right)}{Rp} = \frac{\left( {{Vp} - {Vcst}} \right.}{Rrd}$

If the above equation is solved,

Rrd(Vd−Vp)=Rp(Vp−Vcst)

(Rp+Rrd)Vp=Rrd×Vd+Rp+Vcst,

Vp is as follows.

${Vp} = {{\frac{Rrd}{\left( {{Rp} + {Rrd}} \right)} \times {Vd}} + {\frac{Rp}{\left( {{Rp} + {Rrd}} \right)} \times {Vcst}}}$

Thus, the magnitude of the voltage applied to the second sub-pixelelectrode 191 b is determined by a ratio of the first resistance valueRp of the second switching element Qb and the second resistance valueRrd of the third switching element Qc.

As such, the second pixel voltage Vp applied to the second sub-pixelelectrode 191 b may determine the ratio with the first pixel voltageapplied to the first sub-pixel electrode 191 a, by controlling the firstresistance value Rp of the second switching element Qb and the secondresistance value Rrd of the third switching element Qc.

Also, the resistance R of the thin film transistor is proportional tothe channel length L of the thin film transistor, and is inverselyproportional to the channel width W.

$R \propto \frac{O}{W}$

Accordingly, by controlling the channel length L and the channel width Wof the second switching element Qb and the third switching element Qc,the ratio of the second voltage applied to the second sub-pixelelectrode 191 b to the first voltage applied to the first sub-pixelelectrode 191 a may be controlled.

According to the liquid crystal display of another exemplary embodimentof the present invention, the ratio of the second voltage applied to thesecond sub-pixel electrode 191 b to the first voltage applied to thefirst sub-pixel electrode 191 a may be controlled in other manner, sothat the first pixel and the second pixel can be made to displaydifferent colors.

The liquid crystal display according to an exemplary embodiment of thepresent invention may include first pixel PXA and second pixel PXBdisplaying different colors, and a first ratio between a first valuewhich is the ratio of the channel length to the channel width of thesecond switching element Qb of the first pixel PXA and a second valuewhich is the ratio of the channel length to the channel width of thethird switching element Qc may be different from a second ratio betweena third value which is the ratio of the channel length to the channelwidth of the second switching element Qb of the second pixel PXB and afourth value which is the ratio of the channel length to the channelwidth of the third switching element Qc. For example, the first ratio ofthe first pixel PXA may be smaller or larger than the second ratio ofthe second pixel PXB.

Again referring to FIG. 1, one pixel area of the liquid crystal displayaccording to the present exemplary embodiment is formed of a firstregion R1 where the second subregion 191 a 2 of the first sub-pixelelectrode 191 a is disposed, a second region R2 where a portion of thefirst subregion 191 a 1 of the first sub-pixel electrode 191 a and thesecond branch electrodes 195 of the second sub-pixel electrode 191 boverlap, and a third region R3 where the second branch electrodes 195 ofthe second sub-pixel electrode 191 b are disposed.

The first region R1, the second region R2, and the third region R3 eachhave four subregions according to the direction that the first branchelectrodes 194 of the first sub-pixel electrode 191 a and the secondbranch electrodes 195 of the second sub-pixel electrode 191 b extend,respectively.

The area of the second region R2 may be about two times the area of thefirst region R1. A sum of the area of the third region R3 and the areaof the third region R3 may be about three times the area of the secondregion R2, and may be about six times the area of the first region R1.

Next, the first region R1, the second region R2, and the third region R3of one pixel area of the liquid crystal display according to the presentexemplary embodiment will be described with reference to FIG. 5 to FIG.7.

Referring to FIG. 5, the first region R1 of one pixel area of the liquidcrystal display according to the present exemplary embodiment isdisposed in the first display panel 100, and the second subregion 191 a2 and the common electrode 270 disposed in the second display panel 200together generate the electric field. The second subregion 191 a 2 ofthe first sub-pixel electrode 191 a includes the crossed-shape stem andthe plurality of first branch electrodes 194 extending in four differentdirections. The plurality of first branch electrodes 194 may be inclinedby about 40 degrees with reference to the gate line 121. By a fringefield generated by the edges of the plurality of the first branchelectrodes 194, the liquid crystal molecules of the liquid crystal layer3 disposed in the first region R1 are inclined in four differentdirections. In detail, since the horizontal component of the fringefield formed by the plurality of first branch electrodes 194 isperpendicular to the sides of the plurality of first branch electrodes194, the liquid crystal molecules are affected by the fringe field atboth sides of the plurality of first branch electrodes 194, therebybeing inclined parallel to the length directions of the branchelectrodes 194.

Referring to FIG. 6, the second region R2 of one pixel area of theliquid crystal display according to the present exemplary embodimentoverlaps the plurality of second branch electrodes 195 of the secondsub-pixel electrode 191 b disposed in the first display panel 100 andthe first subregion 191 a 1 of the first sub-pixel electrode 191 a.Accordingly, the liquid crystal molecules of the liquid crystal layer 3are arranged by the electric field formed between the plurality ofsecond branch electrodes 195 of the second sub-pixel electrode 191 b andthe common electrode 270.

Since the plurality of second branch electrodes 195 extend in directionsparallel to those of the plurality of first branch electrodes 194, theliquid crystal molecules of the liquid crystal layer 3 disposed in thesecond region R2 are inclined in four different directions like theliquid crystal molecules of the liquid crystal layer 3 disposed in thefirst region R1.

Next, referring to FIG. 7, the third region R3 of one pixel area of theliquid crystal display according to the present exemplary embodimentgenerates an electric field along the plurality of second branchelectrodes 195 of the second sub-pixel electrode 191 b disposed in thefirst display panel 100 and the common electrode 270 disposed in thesecond display panel 200. Since the plurality of second branchelectrodes 195 extend directions parallel to those of the plurality offirst branch electrodes 194, the liquid crystal molecules of the liquidcrystal layer 3 disposed in the third region R3 are inclined in fourdifferent directions like the liquid crystal molecules of the liquidcrystal layer 3 disposed in the first region R1 and the second regionR2.

As described above, the magnitude of the second voltage applied to thesecond sub-pixel electrode 191 b is smaller than the magnitude of thefirst voltage applied to the first sub-pixel electrode 191 a.

Accordingly, the intensity of the electric field applied to the liquidcrystal layer disposed in the first region R1 is largest, and theintensity of the electric field applied to the liquid crystal layerdisposed in the third region R3 is smallest. Since the influence of theelectric field of the first sub-pixel electrode 191 a disposed under thesecond sub-pixel electrode 191 b exists in the second region R2, theintensity of the electric field applied to the liquid crystal layerdisposed in the second region R2 is smaller than the intensity of theelectric field applied to the liquid crystal layer disposed in the firstregion R1 and is larger than the intensity of the electric field appliedto the liquid crystal layer disposed in the third region R3.Accordingly, the intensity of the electric field applied to the liquidcrystal layer 3 is decreased in order from the first region R1, to thesecond region R2, and to the third region R3.

Thus, in the liquid crystal display according to an exemplary embodimentof the present invention, by dividing one pixel area into three regionswhere the intensity of the electric field applied to the liquid crystallayer 3 is different, the inclination angle of the liquid crystalmolecules is different in each region, and the luminance of each regionis differentiated. As described above, if one pixel area is divided intothree regions having different luminance, by smoothly controlling thechange of the transmittance according to the gray, the transmittanceaccording to the gray change may be prevented from being sharply changedin the high gray as well as the low gray, thereby correctly expressingthe gray in the low gray and the high gray while side visibility isclose to front visibility.

Also, because there is little separation interval between adjacentregions R1, R2 and R3, even though one pixel area is divided into aplurality of regions where the intensity of the electric field appliedto the liquid crystal layer 3 is different, transmittance reduction ofthe pixel area may be prevented.

Also, as described above, the liquid crystal display according to anexemplary embodiment of the present invention may include the firstpixel PXA and the second pixel PXB displaying the different colors,where a first ratio between a first value that is the ratio of thechannel length to the channel width of the second switching element Qbof the first pixel PXA, to a second value that is the ratio of thechannel length to the channel width of the third switching element Qcmay be different from a second ratio between a third value that is theratio of the channel length to the channel width of the second switchingelement Qb of the second pixel PXB, and a fourth value that is the ratioof the channel length to the channel width of the third switchingelement Qc. Thus, in the first pixel PXA and the second pixel PXB, bydifferentiating the ratio of the channel length to the channel width ofthe second switching element Qb and the ratio of the channel length tothe channel width of the third switching element Qc, the ratio of thefirst voltage of the first sub-pixel electrode 191 a and the secondvoltage applied to the second sub-pixel electrode 191 b may be set to bedifferent in the first pixel PXA than in the second pixel PXB.Accordingly, the luminances of the first pixel PXA and the second pixelPXB may be controlled to be different, thereby controlling a hue angle.For example, when the first pixel PXA displays red or green and thesecond pixel PXB displays blue, if the ratios of channel width tochannel length of the second switching element Qb and the thirdswitching element Qc are set so that the luminance of the second pixelPXB is larger than the luminance of the first pixel PXA, the blueluminance of the displayed color is increased. In detail, for example,by forming the ratio of the second voltage to the first voltage of thepixel displaying blue to be larger than the ratios of the second voltageto the first voltage of the pixels displaying red and green, the blueluminance may be increased, thereby controlling the hue angle.

In this way, in the liquid crystal display according to an exemplaryembodiment of the present invention, by controlling the ratio of thevoltages applied to the first sub-pixel electrode 191 a and the secondsub-pixel electrode 191 b of the first pixel PXA and the second pixelPXB displaying different colors, the hue angle of the displayed colormay be controlled.

Next, the liquid crystal display according to another exemplaryembodiment of the present invention will be described with reference toFIG. 8 to FIG. 10 as well as FIG. 1 to FIG. 4. FIG. 8 is a layout viewof a second pixel of a liquid crystal display according to anotherexemplary embodiment of the present invention. FIG. 9 is a layout viewof a first sub-pixel electrode of a second pixel of the liquid crystaldisplay of FIG. 8. FIG. 10 is a layout view of a portion of a firstsub-pixel electrode and a second sub-pixel electrode of a second pixelof the liquid crystal display of FIG. 8.

The liquid crystal display according to the present exemplary embodimentincludes the first pixel PXA displaying the first color and a secondpixel PXB displaying the second color.

The first pixel PXA includes a first sub-pixel electrode 191 a and asecond sub-pixel electrode 191 b as in the exemplary embodiment shown inFIG. 1 to FIG. 4.

As described above, the first subregion 191 a 1 of the first sub-pixelelectrode 191 a of the first pixel PXA has a cross-shaped connectionportion disposed in the center portion of the pixel area, and fourparallelograms enclosing the cross-shaped connection portion. The firstextension portion 193 is disposed in the center of the cross-shapedconnection portion. Also, the first extension portion 193 has aprotrusion extending upwardly and downwardly from the transverse centerportion of the pixel area. Thus, the first subregion 191 a 1 of thefirst sub-pixel electrode 191 a is disposed within the pixel area.

The second subregion 191 a 2 of the first sub-pixel electrode 191 a ofthe first pixel PXA is disposed in the center portion of the pixel, andits outer edges outline a generally rhomboid shape when viewed in planview. The second subregion 191 a 2 of the first sub-pixel electrode 191a includes the cross-shaped stem including the transverse portion andthe longitudinal portion, and the plurality of first branch electrodes194 extending from the crossed-shape stem. The first branch electrodes194 extend in four directions.

The second sub-pixel electrode 191 b of the first pixel PXA is formed toenclose or at least partially surround the second subregion 191 a 2 ofthe first sub-pixel electrode 191 a, and includes the outer stem 192 aformed to enclose the second subregion 191 a 2 of the first sub-pixelelectrode 191 a and the plurality of second branch electrodes 195extending from the outer stem 192 a.

Each portion of the second branch electrodes 195 of the second sub-pixelelectrode 191 b of the first pixel PXA overlaps the first subregion 191a 1 of the first sub-pixel electrode 191 a.

Referring to FIG. 8 to FIG. 10, the first sub-pixel electrode 191 a andthe second sub-pixel electrode 191 b of the second pixel PXB of theliquid crystal display according to the present exemplary embodimenthave similar shapes as the first sub-pixel electrode 191 a and thesecond sub-pixel electrode 191 b of the first pixel PXA described withreference to FIG. 1 to FIG. 4. The interlayer structure is substantiallythe same. Accordingly, detailed description of each layer is omitted.

However, as shown in FIG. 8 to FIG. 10, the first subregion 191 a 1 ofthe first sub-pixel electrode 191 a of the second pixel has across-shaped connection portion disposed at the center of the pixel areaand four parallelograms which are disposed around the cross-shapedconnection portion to surround the cross-shaped connection portion. Thefirst extension portion 193 is disposed at the center of thecross-shaped connection portion. Further, a protrusion extending upwardand downward from a horizontal center of the pixel area is formed. Assuch, the first subregion 191 a 1 of the first subpixel electrode 191 ais disposed within the pixel area.

The second subregion 191 a 2 of the first sub-pixel electrode 191 a ofthe second pixel PXB is disposed at the central portion of the pixel,and the overall shape thereof is rhomboidal, i.e. as above its outeredges outline a generally rhomboid shape in plan view. The secondsubregion 191 a 2 of the first subpixel electrode 191 a includes across-shaped stem including the transverse part and the longitudinalpart, and a plurality of first branch electrodes 194 extending from thecross-shaped stem. The first branch electrodes 194 extend in fourdifferent directions.

The second sub-pixel electrode 191 b of the second pixel PXB is formedto enclose the second subregion 191 a 2 of the first sub-pixel electrode191 a, and includes the outer stem 192 a formed to enclose the secondsubregion 191 a 2 of the first sub-pixel electrode 191 a and theplurality of second branch electrodes 195 extending from the outer stem192 a.

Each portion of the second branch electrodes 195 of the second sub-pixelelectrode 191 b of the second pixel PXB overlaps a portion of the firstsubregion 191 a 1 of the first sub-pixel electrode 191 a.

A first angle θ1 between the first branch electrodes 194 of the firstpixel PXA and the gate line 121 is different from a second angle θ2between the first branch electrodes 194 of the second pixel PXB and thegate line 121. In detail, the first angle θ1 may be about 40 degrees,and the second angle θ2 may be about 45 degrees, although any numericalvalues are contemplated for θ1 and θ2, subject to the above constraints.

When the polarization axis of the polarizer (not shown) attached outsidethe first display panel 100 and/or the second display panel 200 forms anangle of about 45 degrees with the gate line 121, the luminance of thesecond pixel PXB is higher than that of the first pixel PXA. In thisway, by differentiating the luminance of the first pixel PXA and thesecond pixel PXB displaying different colors, the hue angle may becontrolled. For example, when the first pixel PXA displays red or greenand the second pixel PXB displays blue, if the angle θ1 of the firstpixel PXA is set so that the luminance of the second pixel PXB is largerthan the luminance of the first pixel PXA, the blue luminance of thedisplayed color is increased.

Thus, in the liquid crystal display according to an exemplary embodimentof the present invention, by controlling the angle θ1 of the first pixelPXA and the second pixel PXB displaying different colors, the hue angleof the displayed color may be controlled.

Next, the liquid crystal display according to another exemplaryembodiment of the present invention will be described with reference toFIG. 11 to FIG. 13 as well as FIG. 1 to FIG. 4. FIG. 11 is a layout viewof a second pixel of a liquid crystal display according to anotherexemplary embodiment of the present invention. FIG. 12 is a layout viewof a first sub-pixel electrode of a second pixel of the liquid crystaldisplay of FIG. 11. FIG. 13 is a layout view of a portion of a firstsub-pixel electrode and a second sub-pixel electrode of a second pixelof the liquid crystal display of FIG. 11.

The liquid crystal display according to the present exemplary embodimentincludes the first pixel PXA displaying the first color and the secondpixel PXB displaying the second color.

The first pixel PXA includes the first sub-pixel electrode 191 a and thesecond sub-pixel electrode 191 b, as in the exemplary embodiment shownin FIG. 1 to FIG. 4.

As described above, the first subregion 191 a 1 of the first sub-pixelelectrode 191 a of the first pixel PXA has a cross-shaped connectionportion disposed in the center portion of the pixel area, and fourparallelograms enclosing the cross-shaped connection portion. The firstextension portion 193 is disposed in the center of the cross-shapedconnection portion. Also, the first extension portion 193 has theprotrusion extending upwardly and downwardly from the transverse centerportion of the pixel area. In this way, the first subregion 191 a 1 ofthe first sub-pixel electrode 191 a is disposed within the pixel area.

The second subregion 191 a 2 of the first sub-pixel electrode 191 a ofthe first pixel PXA is disposed in the center portion of the pixel, andas above has a generally rhomboid shape. The second subregion 191 a 2 ofthe first sub-pixel electrode 191 a includes the crossed-shape stemincluding the transverse portion and the longitudinal portion, and theplurality of first branch electrodes 194 extending from thecrossed-shape stem. The first branch electrodes 194 extend in fourdirections.

The second sub-pixel electrode 191 b of the first pixel PXA is formed toenclose or at least partially surround the second subregion 191 a 2 ofthe first sub-pixel electrode 191 a, and includes the outer stem 192 aformed to enclose the second subregion 191 a 2 of the first sub-pixelelectrode 191 a and the plurality of second branch electrodes 195extending from the outer stem 192 a.

Parts of the second branch electrodes 195 of the second sub-pixelelectrode 191 b of the first pixel PXA overlap the first subregion 191 a1 of the first sub-pixel electrode 191 a.

Referring to FIG. 11 to FIG. 13, the first sub-pixel electrode 191 a andthe second sub-pixel electrode 191 b of the second pixel PXB of theliquid crystal display according to the present exemplary embodiment areshaped similar to the first sub-pixel electrode 191 a and the secondsub-pixel electrode 191 b of the first pixel PXA described withreference to FIG. 1 to FIG. 4. The interlayer structure is substantiallythe same. Accordingly, detailed description of each layer is omitted.

However, as shown in FIG. 11 to FIG. 13, the first subregion 191 a 1 ofthe first sub-pixel electrode 191 a of the second pixel has across-shaped connection portion disposed at the center of the pixelarea, and sides of subregion 191 a 1 outline four parallelograms whichare disposed around the cross-shaped connection portion to surround thecross-shaped connection portion. The first extension portion 193 isdisposed at the center of the cross-shaped connection portion. Further,a protrusion extending upward and downward from a horizontal center ofthe pixel area is formed. As such, the first subregion 191 a 1 of thefirst subpixel electrode 191 a is disposed at a part of the pixel area.

The second subregion 191 a 2 of the first sub-pixel electrode 191 a ofthe second pixel PXB is disposed at the central portion of the pixel,and outer edges thereof outline a generally rhomboidal shape. The secondsubregion 191 a 2 of the first subpixel electrode 191 a includes across-shaped stem including the transverse part and the longitudinalpart, and a plurality of first branch electrodes 194 extending from thecross stem. The first branch electrodes 194 extend in four differentdirections.

The second sub-pixel electrode 191 b of the second pixel PXB is formedto at least partially surround or enclose the second subregion 191 a 2of the first sub-pixel electrode 191 a, and includes the outer stem 192a formed to enclose the second subregion 191 a 2 of the first sub-pixelelectrode 191 a. Also included is the plurality of second branchelectrodes 195 extending from the outer stem 192 a.

Some of the second branch electrodes 195 of the second sub-pixelelectrode 191 b of the second pixel PXB overlap the first subregion 191a 1 of the first sub-pixel electrode 191 a.

Referring to FIG. 11 to FIG. 13 along with FIG. 1 to FIG. 4, the areacovered by the second subregion 191 a 2 of the first sub-pixel electrode191 a of the second pixel PXB is larger than the area covered by thesecond subregion 191 a 2 of the first sub-pixel electrode 191 a of thefirst pixel PXA.

By increasing the size of the second subregion 191 a 2 of the firstsub-pixel electrode 191 a, the luminances of the first pixel PXA and thesecond pixel PXB may be differentiated. The size of the second subregion191 a 2 of the second pixel PXB is larger than the first size of thesecond subregion 191 a 2 of the first pixel PXA, so that the luminanceof the second pixel PXB is higher than the luminance of the first pixelPXA.

Thus, by differentiating the luminances of the first pixel PXA and thesecond pixel PXB displaying different colors, the hue angle may becontrolled. For example, if the first pixel PXA displays red or greenand the second pixel PXB displays blue and the size of the secondsubregion 191 a 2 of the second pixel PXB is larger than the size of thesecond subregion 191 a 2 of the first pixel PXA, the blue luminance isincreased.

In the liquid crystal display according to an exemplary embodiment ofthe present invention, by controlling the sizes of the second subregions191 a 2 of the first pixel PXA and the second pixel PXB displayingdifferent colors, the hue angle of the displayed color may be bettercontrolled.

Next, experimental results of testing of a display constructed accordingto the present invention will be described with reference to FIG. 14 andFIG. 15. FIG. 14 and FIG. 15 are graphs showing results of testing of adisplay constructed according to an embodiment of the present invention.

FIG. 14 illustrates a first case in which the ratio of the secondvoltage applied to the second sub-pixel electrode 191 b to the firstvoltage applied to the first sub-pixel electrode 191 a of three pixelsdisplaying red, green, and blue is about 0.65. In contrast, FIG. 15illustrates a second case in which the ratio of the second voltageapplied to the second sub-pixel electrode 191 b to the first voltageapplied to the first sub-pixel electrode 191 a of the pixels displayingred and green is about 0.65, and the ratio of the second voltage appliedto the second sub-pixel electrode 191 b to the first voltage applied tothe first sub-pixel electrode 191 a of the pixel displaying blue isabout 0.7. For these cases, the transmittance change as a function ofgray in the front and the transmittance change as a function of gray atthe lateral side are measured, and results are shown in FIG. 14 and FIG.15.

Referring to FIG. 14, in the first case, a transmittance curve of blueat the lateral side is different from the transmittance curves of redand green. Particularly, the transmittance of blue is lower than thetransmittances of red and green from gray values of about 22 to about40. However, referring to FIG. 15, in the second case, the transmittancecurve of blue at the lateral side is almost the same as thetransmittance curves of red and green. This demonstrates that, bycontrolling the ratio of the second voltage of the second sub-pixelelectrode 191 b to the first voltage applied to the first sub-pixelelectrode 191 a, the transmittance for each gray of the displayed colormay be controlled.

Next, further experimental results from testing a display according tothe present invention will be described with reference to FIG. 16 andFIG. 17. FIG. 16 and FIG. 17 are graphs showing results of furthertesting of a display according to the present invention.

FIG. 16 presents results for a first case in which the ratio of thesecond voltage applied to the second sub-pixel electrode 191 b to thefirst voltage applied to the first sub-pixel electrode 191 a for threepixels displaying red, green, and blue is about 0.65. FIG. 17 presentsresults for a second case in which the ratio of the second voltageapplied to the second sub-pixel electrode 191 b to the first voltageapplied to the first sub-pixel electrode 191 a for the pixels displayingred and green is about 0.65, and the ratio of the second voltage appliedto the second sub-pixel electrode 191 b to the first voltage applied tothe first sub-pixel electrode 191 a of the pixel displaying blue isabout 0.7. For these cases, the hue angle for the gray is measured, andresults thereof are shown in FIG. 16 and FIG. 17.

Referring to FIG. 16, in the first case, the hue angle A1 for each grayat the lateral side is significantly different from the hue angle B foreach gray viewed from the front. However, referring to FIG. 17, in thesecond case, the difference between the hue angle A2 for each gray atthe lateral side and the hue angle B for each gray in the front issignificantly less than that of the first case. This demonstrates thathue angle may be controlled by controlling the ratio of the secondvoltage of the second sub-pixel electrode 191 b to the first voltageapplied to the first sub-pixel electrode 191 a.

Next, further experimental results will be described with reference toFIG. 18. FIG. 18 is a graph showing further experimental results oftesting of a display corresponding to an embodiment of the presentinvention.

In the present experimental example, the ratio of the second voltageapplied to the second sub-pixel electrode 191 b to the first voltageapplied to the first sub-pixel electrode 191 a of the first pixel PXAand the second pixel PXB is set to about 0.7. Then, FIG. 18 showsmeasured results for two cases. In the first case, the area ratio of thefirst region R1, the second region R2, and the third region R3 for thered pixel, the green pixel, and the blue pixel is 1:1.6:4.9. In thesecond, the area ratio of the first region R1, the second region R2, andthe third region R3 for the red pixel and the green pixel is 1:1.6:4.9,while the area ratio of the first region R1, the second region R2, andthe third region R3 for the blue pixel as 1:1.2:3.7. The hue angle for askin gray is measured and a result thereof is shown in FIG. 18.

Referring to FIG. 18, in the curve D2 of the second case in which theratio of the first region R1 of the blue pixel is relatively highcompared with the curve D1 of the first case, the magnitude of the hueangle is reduced for the case that the value of the skin gray is large.

The skin gray is a gray value measured after setting the ratio ofred:green:blue as 1:0.7:0.6. As the magnitude of the hue angle for thevalue of the skin gray is decreased, blue in the colors is increased,and as the magnitude of the hue angle is increased, the color becomesyellowish.

Accordingly, by controlling the magnitude of the high pixel of thepixels displaying the different colors, the hue angle as a function ofgray value may be controlled.

Thus, by including a first pixel and a second pixel displaying differentcolors and by controlling the ratio of the magnitude of the voltageapplied to the second sub-pixel electrode to the magnitude of thevoltage applied to the first sub-pixel electrode for the first pixel andthe second pixel, the luminance of the first pixel and the second pixelmay be controlled, thereby controlling the hue angle.

Also, by including pixels of two different colors and by controlling theorientation of the plurality of branch electrodes of the first sub-pixelelectrode and the second sub-pixel electrode of the first pixel and thesecond pixel, the luminance of the first pixel and the second pixel maybe controlled, thereby further controlling the hue angle.

Also, by controlling the first pixel and the second pixel and bycontrolling the areas of the first sub-pixel electrode and the secondsub-pixel electrode of the first pixel and the second pixel, theluminance of the first pixel and the second pixel may be controlled,thereby still further controlling the hue angle.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims. Furthermore, different features of thevarious embodiments, disclosed or otherwise understood, can be mixed andmatched in any manner to produce further embodiments within the scope ofthe invention.

<Description of symbols> 100, 200: display panel 110, 210: substrate124a, 124b, 124c: gate electrode 140: gate insulating layer 154a, 154b,154c: semiconductor 171: data line 173a, 173b, 173c: source electrode175a, 175b, 175c: drain electrode 180a, 180b: passivation layer 191a,191b: sub-pixel electrode 194, 195: branch electrode 220: light blockingmember 230: color filter 270: common electrode 3: liquid crystal layerPXA, PXB: pixel R1: first region R2: second region R3: third region

What is claimed is:
 1. A liquid crystal display comprising: a first pixel and a second pixel displaying different colors, the first pixel and the second pixel each comprising: a first substrate; a first sub-pixel electrode disposed on the first substrate and receiving a first voltage; a second sub-pixel electrode disposed on the first substrate and receiving a second voltage; an insulating layer disposed between the first sub-pixel electrode and the second sub-pixel electrode; a second substrate facing the first substrate; and a common electrode disposed on the second substrate and receiving a common voltage, wherein: a first portion of the first sub-pixel electrode and a second portion of the second sub-pixel electrode overlap each other, a difference between the first voltage and the common voltage is larger than a difference between the second voltage and the common voltage, and a ratio of the second voltage to the first voltage for the first pixel is different from a ratio of the second voltage to the first voltage for the second pixel.
 2. The liquid crystal display of claim 1, further comprising: a first switching element connected to the first sub-pixel electrode; and a second switching element and a third switching element connected to the second sub-pixel electrode, wherein a ratio of a channel length to a channel width of one of the second switching element and the third switching element of the first pixel is different from a ratio of the channel length to the channel width of one of the second switching element and the third switching element of the second pixel.
 3. The liquid crystal display of claim 2, wherein the first portion of the first sub-pixel electrode includes a first subregion disposed under the insulating layer and a second subregion disposed on the insulating layer, and the first subregion and the second subregion are connected to each other through a contact hole formed in the insulating layer.
 4. The liquid crystal display of claim 3, further comprising a gate line formed on the first substrate, and wherein the second subregion of the first sub-pixel electrode includes a plurality of first branch electrodes, the second sub-pixel electrode includes a plurality of second branch electrodes, and a first angle between the first branch electrodes of the second subregion of the first pixel and the gate line is different from a second angle between the first branch electrodes of the second subregion of the second pixel and the gate line.
 5. The liquid crystal display of claim 4, wherein a size of an area of the second subregion of the first pixel is different from a size of an area of the second subregion of the second pixel.
 6. The liquid crystal display of claim 5, wherein the first portion of the first sub-pixel electrode is substantially planar, and the second branch electrodes collectively extend along a plurality of different directions.
 7. The liquid crystal display of claim 1, wherein the first portion of the first sub-pixel electrode includes a first subregion disposed under the insulating layer and a second subregion disposed on the insulating layer, and the first subregion and the second subregion are connected to each other through a contact hole formed in the insulating layer.
 8. The liquid crystal display of claim 7, further comprising a gate line formed on the first substrate, and wherein the second subregion of the first sub-pixel electrode includes a plurality of first branch electrodes, the second sub-pixel electrode includes a plurality of second branch electrodes, and a first angle between the first branch electrodes of the second subregion of the first pixel and the gate line is different from a second angle between the first branch electrodes of the second subregion of the second pixel and the gate line.
 9. The liquid crystal display of claim 8, wherein an area of the second subregion of the first pixel is substantially the same size as an area of the second subregion of the second pixel.
 10. The liquid crystal display of claim 9, wherein the first portion of the first sub-pixel electrode is substantially planar, and the second branch electrodes collectively extend along a plurality of different directions.
 11. The liquid crystal display of claim 7, wherein an area of the second subregion of the first pixel is substantially the same size as an area of the second subregion of the second pixel.
 12. The liquid crystal display of claim 11, wherein the first portion of the first sub-pixel electrode is substantially planar, and the second branch electrodes collectively extend along a plurality of different directions.
 13. A liquid crystal display comprising: a first pixel and a second pixel displaying different colors, the first pixel and the second pixel each comprising: a first substrate; a first sub-pixel electrode disposed on the first substrate and receiving a first voltage; a second sub-pixel electrode disposed on the first substrate and receiving a second voltage; and an insulating layer disposed between the first sub-pixel electrode and the second sub-pixel electrode, wherein one pixel area includes a first region where a first portion of the first sub-pixel electrode is disposed, a second region where the second portion of the first sub-pixel electrode and a third portion of the second sub-pixel electrode overlap each other, and a third region where a fourth portion of the second sub-pixel electrode is disposed, and a ratio of the second voltage to the first voltage of the first pixel is different from a ratio of the second voltage to the first voltage of the second pixel.
 14. The liquid crystal display of claim 13, further comprising: a first switching element connected to the first sub-pixel electrode; and a second switching element and a third switching element connected to the second sub-pixel electrode, wherein a ratio of a channel length to a channel width of one of the second switching element and the third switching element of the first pixel is different from a ratio of a channel length to a channel width of one of the second switching element and the third switching element of the second pixel.
 15. The liquid crystal display of claim 14, further comprising a gate line formed on the first substrate, and wherein the second subregion of the first sub-pixel electrode includes a plurality of first branch electrodes, and a first angle between the first branch electrodes of the first pixel and the gate line is different from a second angle between the first branch electrodes of the second pixel and the gate line.
 16. The liquid crystal display of claim 15, wherein a size of an area of the first portion of the first pixel is substantially the same as a size of an area of the first portion of the second pixel.
 17. The liquid crystal display of claim 16, wherein the second portion of the first sub-pixel electrode is substantially planar, and the second branch electrodes collectively extend along a plurality of different directions.
 18. The liquid crystal display of claim 13, wherein further comprising a gate line formed on the first substrate, and wherein the first portion of the first sub-pixel electrode includes a plurality of first branch electrodes, and a first angle between the first branch electrodes of the first pixel and the gate line is different from a second angle between the first branch electrodes of the second pixel and the gate line.
 19. The liquid crystal display of claim 18, wherein an area of the first portion of the first pixel is substantially the same size as an area of the first portion of the second pixel.
 20. The liquid crystal display of claim 19, wherein the second portion of the first sub-pixel electrode is substantially planar, and the second branch electrodes collectively extend along a plurality of different directions.
 21. The liquid crystal display of claim 13, wherein an area of the first portion of the first pixel is substantially the same size as an area of the first portion of the second pixel.
 22. The liquid crystal display of claim 21, wherein the second portion of the first sub-pixel electrode is substantially planar, and the second branch electrodes collectively extend along a plurality of different directions. 